This invention relates to an elongate edging strip for trimming the edges of panels, such as tiles, used in building work.
Such products are known and generally comprise, in profile, a leg section which extends under the tiles and is embedded in a tile adhesive, and an upstanding section which is of a height such that its top edge lies approximately on the same plane as the outer surface of the tiles, and therefore acts to protect the vulnerable edges of the tiles from being chipped. The outward facing surface of the strip is preferably a decorative surface and may be curved or provided with some other decorative shape to provide an aesthetically pleasing edge to the tiles, or may simply be painted in an attractive colour, or provided with a decorative printed or embossed finish.
Existing products are generally fabricated as an elongate extrusion of plastics material such as polyethylene or polypropylene.
The present invention seeks to provide an improved edging strip.
In accordance with a first aspect of the invention there is provided an elongate edging strip made out of an extruded material, characterised in that the material is a vinylaromatic homopolymer or copolymer. Examples of such materials include styrene based materials, such as polystyrene, polystyrene alloy or ABS (acrylonitrile butadiene styrene).
Vinylaromatic materials have a number of advantages over the currently used materials. For example, polystyrene is considered to be more environmentally friendly than the current most commonly-used material, which is PVCu. Also the surface of polystyrene is such as to exhibit, improved performance when used with adhesive, particularly ceramic tile adhesive. This in turn has enabled a simpler construction to be used, with a reduced need for special formations or apertures to be formed on the leg section of the profile. For example most current PVCu edging strips rely on the adhesive being squeezed through holes which are punched at intervals during manufacture along the length of the leg section. The formation of these holes requires an extra manufacturing step and increases the cost of the product. Using polystyrene, we have found that there is no need for these holes and, indeed, the length of the leg section, in profile, can be shortened, thus saving material costs.
Due to its relatively high surface energy and chemical structure, polystyrene readily accepts a number of decorative finishes, so that the front surface of the upstanding section of the profile can be given a desired decorative effect. For example, polystyrene readily accepts paints and hot stamp decorative foils to achieve levels of gloss sufficient to emulate glazed ceramic.
By contrast, polyethylene and polypropylene materials have a naturally oily surface and PVCu compounds have lubricant added during their manufacture. These materials do not have an xe2x80x9cinstant grabxe2x80x9d to ceramic tile adhesive and they often require pre-treatment prior to paint finishing due to their low surface energy.
In a preferred embodiment the edging strip comprises a skin made of solid material and a core made of foamed material. For example, the strip may be co-extruded with a solid styrene skin and a foamed styrene core.
In accordance with a second aspect of the invention there is provided a method of making an elongate edging strip comprising, in profile, a leg section and an upstanding section, said method comprising forming by extrusion an elongate profile comprising a base section and two spaced upstanding sections, said base section being formed with a longitudinal line of weakness extending between said upstanding sections, and thence breaking the profile apart along the line of weakness to form a pair of said edging strips. The two edging strips formed in this way would normally be identical, but they do not have to be so. Any decorative finish to be applied to the upstanding portions can be applied either before or after breaking the profile.
The edging strip may be made of any suitable material, but is preferably made from a vinylaromatic homopolymer or copolymer, such as polystyrene, in the manner described above.